This invention relates in general to foundations for buildings and more particularly to an apparatus and process for stabilizing or shoring such foundations.
The traditional procedure for shoring a foundation requires boring a hole into the soil adjacent to the foundation, preferably to bedrock, and then pouring concrete into the hole and beneath the footing of the foundation. The concrete sets up into a solid, cast in place, pier which provides a more stable support than the underlying soil. This procedure can be quite complex and costly, and just as disturbing, results in a considerable amount of damage to lawn and shrubbery, owing to the extensive excavation that is required.
U.S. Pat. No. 4,708,528 describes a less complex procedure that requires very little, if any, excavation. In this procedure a hole is drilled into the foundation wall and a bracket is engaged with the wall at the hole. The bracket has a sleeve and a pin projected from the sleeve, and it is the latter which fits into the hole in the foundation, leaving the sleeve exposed at the face of the foundation. Pier sections are then forced, one after the other, through the sleeve until the pier so formed reaches bedrock. To this end, a so-called jack stand is temporarily attached to the sleeve, and it has a hydraulic jack which bears against the uppermost pier section and forces the entire pier downwardly. Of course, the downwardly directed force that is applied to the pier creates an upwardly directed reaction force, but the jack stand and bracket transfer the reaction force to the foundation which resists it.
The shoring system set forth in U.S. Pat. No. 4,708,528 serves quite well for stabilizing foundations having monolithic walls of substantial height such as those formed from poured concrete for basements or crawl spaces in colder climates where some depth is required to get below the first line. It is less suited for foundations having weaker walls. Typical of such weaker foundations are those formed from blocks laid up in tiers and those used along slabs in warmer climates. The latter appear as concrete beams in that they have relatively little depth.
The present invention resides in a foundation shoring system that is ideally suited for stabilizing relatively weak foundations such as those formed from blocks laid up in tiers or along peripheries of slabs on grade. While it utilizes a bracket having a sleeve through which the pier sections are forced, the sleeve does not engage the foundation through a single pin, but instead through a plate which is against the foundation wall and is secured to the wall with several bolts or other fasteners. The plate covers a significant area of the foundation wall.